Process for the preparation of polyether polyols

ABSTRACT

The present invention provides a process for conditioning double metal cyanide (DMC) catalysts, which are employed in the preparation of polyether polyols based on starter compounds having active hydrogen atoms, the preparation of polyether polyols using the conditioned catalysts and the use of the polyether polyols prepared in this way for the preparation of polyurethane materials.

FIELD OF THE INVENTION

The present invention provides a process for conditioning double metalcyanide catalysts (“DMC catalysts”), which are employed in thepreparation of polyether polyols based on starter compounds havingactive hydrogen atoms, the preparation of polyether polyols using theconditioned catalysts and the use of the polyether polyols prepared inthis way for the preparation of polyurethane materials.

BACKGROUND OF THE INVENTION

Polyether polyols which are suitable for the preparation of polyurethanematerials can be obtained via various preparation processes. On the onehand, the base-catalyzed addition of alkylene oxides to startercompounds having Zerewitinoff-active hydrogen atoms and on the otherhand, the use of double metal cyanide compounds as catalysts for theaddition of alkylene oxides to starter compounds havingZerewitinoff-active hydrogen atoms are of importance on the largeindustrial scale. The (Lewis) acid-catalyzed addition of alkylene oxideson to suitable starter compounds is of minor importance.

The base-catalyzed addition of alkylene oxides, such as, for example,ethylene oxide or propylene oxide, to starter compounds havingZerewitinoff-active hydrogen atoms is carried out in the presence ofalkali metal hydroxides, alkali metal hydrides or also amines, such asN,N-dimethylbenzylamine or imidazole. After the addition of the alkyleneoxides has taken place, the polymerization-active centers on thepolyether chains must be neutralized with dilute mineral acids, such assulfuric acid or phosphoric acid, or also organic acids, such as e.g.lactic acid, and the salts formed must be separated off, if appropriate.Working up of the alkaline polymers is also possible with the aid ofacid laminar silicates or by means of acid cation exchangers. Inamine-catalyzed alkylene oxide addition reactions, further working upcan be omitted if the presence of the amines in these polyether polyolsdoes not impair the preparation of polyurethane materials. In additionto the necessity of the polyether polyols having to be worked up, ifappropriate, before their use as polyurethane components, two furtherdisadvantages of the base-catalyzed addition of alkylene oxides on tostarter compounds having Zerewitinoff-active hydrogen atoms are to bementioned. Only polyethers having relatively low equivalent weights canbe obtained via amine catalysis, in this context see, for example,Ionescu et al. in “Advances in Urethane Science & Technology”, 1998, 14,p. 151-218. Under alkali metal hydroxide catalysis, undesirable sidereactions increase significantly as the molar mass of the polymerincreases. The isomerization of propylene oxide to allyl alcohol, which,at high equivalent weights (or low OH numbers), leads to a high contentof monofunctional polyether species in the reaction mixture, is to bementioned in particular here. The monofunctional polyether moleculeshave an adverse effect on the full curing properties and the profile ofphysical properties of polyurethane systems.

By employing double metal cyanide catalysts, it has become possible tospeed up the addition of alkylene oxides, in particular propylene oxide,to starter compounds having Zerewitinoff-active hydrogen atoms down tovery low OH numbers, without the abovementioned isomerization ofpropylene oxide to allyl alcohol occurring to a noticeable extent.Highly active DMC catalysts, which are described e.g. in U.S. Pat. No.5,470,813, EP-A 700 949, EP-A 743 093, EP-A 761 708, WO 97/40086, WO98/16310 and WO 00/47649, furthermore have an exceptionally highactivity and render possible the preparation of polyether polyols atvery low catalyst concentrations (25 ppm or less), so that it is nolonger necessary to separate off the catalyst from the finished product.Typical examples are the highly active DMC catalysts described in EP-A700 949, which, in addition to a double metal cyanide compound (e.g.zinc hexacyanocobaltate(III)) and an organic complexing ligand (e.g.tert-butanol), also contain a polyether having a number-averagemolecular weight of greater than 500 g/mol.

A characteristic of DMC catalysts is their pronounced sensitivity tohigh concentrations of hydroxyl groups, which can be caused, forexample, by large amounts of starter compounds such as ethylene glycol,propylene glycol, glycerol, trimethylolpropane, sorbitol or sucrose, andpolar impurities of the reaction mixture. The DMC catalysts then cannotbe converted into the polymerization-active form during the reactioninitiation phase. Impurities can be, for example, water, compoundshaving a high number of hydroxyl groups in close proximity, such ascarbohydrates and carbohydrate derivatives, or compounds having basicgroups, such as, for example, amines. Substances having carbonyl groupsin close proximity or carbonyl groups adjacent to hydroxyl groups alsohave an adverse effect on the catalyst activity. In order, nevertheless,to be able to subject starter compounds having high concentrations of OHgroups or starter compounds with impurities which are to be regarded ascatalyst poisons to DMC-catalyzed alkylene oxide addition reactions, theconcentration of hydroxyl groups must be lowered or the catalyst poisonsrendered harmless. For this purpose, in the past prepolymers were firstprepared from these starter compounds by means of base catalysis, and,after thorough working up, it was then possible to convert these intothe desired alkylene oxide addition products of high molar mass by meansof DMC catalysis. An important further development in this connectionwas the development of continuous metering of starter compounds, whichis disclosed in WO 97/29146. In this case critical starter compounds arenot initially introduced into the reactor, but are fed to the reactorcontinuously during the reaction, alongside the alkylene oxides. In thisprocess, prepolymers can be initially introduced into the reactor as thestarting medium for the reaction, and the use of small amounts of theproduct to be prepared itself as the starting medium is also possible.The necessity of having first to prepare prepolymers suitable forfurther alkylene oxide additions separately was eliminated with thelatter procedure.

However, if short-chain polyether alcohols having OH numbers of greaterthan 200 mg KOH/g are to be obtained, it is necessary to increase theratio of starter compound to alkylene oxide in the educt stream meteredin, so that there is again the danger of reaching criticalconcentrations of hydroxyl groups and polar impurities. In such casesthe catalysts increasingly lose activity during the starter compoundmetering phase, which manifests itself e.g. by an increase in pressurein the reactor as a consequence of an increasing concentration of freealkylene oxide.

If compounds of varying purity, for example those which are obtainedfrom renewable sources of raw materials, are employed as startercompounds, unknown secondary components can likewise significantlyimpair the catalyst activity. In this case either the catalyst cannot beconverted into the active form at all, or the loss in activity describedabove is observed.

The problems described on the one hand, can of course be counteracted byan increase in the catalyst concentration, and on the other hand anattempt can also be made to free the starter compounds from impuritiesby suitable pretreatments, such as intensive stripping at temperaturesabove 80° C., distillation or extraction. All these alternatives aretime-consuming and cost-intensive.

SUMMARY OF THE INVENTION

The present invention therefore, provides a process for the treatment ofDMC catalysts which allows high ratios of starter compound to alkyleneoxide to be metered in the continuous starter compound metering processand thus allows polyether polyols having OH numbers of greater than 200mg KOH/g to be rendered accessible without problems, i.e. withoutinvolved pretreatment of the starting medium which has been initiallyintroduced into the reactor or of the starter compounds metered in.Furthermore, the process makes the catalysts robust against any type ofimpurities which impede conversion of the catalyst into thepolymerization-active form. Such impurities can occur, for example, instarter compounds which are obtained from renewable sources of rawmaterials.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described for purposes of illustrationand not limitation. Except in the operating examples, or where otherwiseindicated, all numbers expressing quantities, percentages, OH numbers,functionalities and so forth in the specification are to be understoodas being modified in all instances by the term “about.” Equivalentweights and molecular weights given herein in Daltons (Da) are numberaverage equivalent weights and number average molecular weightsrespectively, unless indicated otherwise.

The present invention provides a process for conditioning of doublemetal cyanide (DMC) catalysts in which these are dispersed attemperatures of from 0 to 80° C., preferably from 20 to 60° C., in aprecursor which is used as the starting medium for the alkoxylationreaction and has an OH number of from 5 to 500 mg KOH/g or a polyetherpolyol which corresponds to the reaction product to be prepared, over aperiod of from 5 min to 4 hours, preferably from 15 min to 2 hours,under an inert gas atmosphere under pressures of from 1 mbar to 10 bar.During this pretreatment, herein referred to as “conditioning”, alkyleneoxides, such as e.g. propylene oxide and/or ethylene oxide, may bepresent. If the conditioning is carried out in the presence of alkyleneoxides, the actual activation of the catalyst, which manifests itself byan accelerated drop in pressure in the reactor, does not yet start inthe conditioning phase.

The present invention also provides a process for the preparation ofpolyether polyols, in which the catalysts conditioned according to theinvention are employed, and the use of the polyether polyols prepared inthis way for the preparation of polyurethane materials.

The polyether polyols prepared with the conditioned catalysts have OHnumbers of from 5 to 500 mg KOH/g. The catalyst concentration in the endproduct is conventionally 10 to 1,000 ppm. The conditioned DMC catalystsare distinguished by a high catalyst activity, which is maintained overthe entire duration of the reaction. While the process according to theinvention is carried out, the partial pressure generated by unreactedalkylene oxide, which is an indicator of the catalyst activity, issignificantly lower than when processes of the current prior art areused, with otherwise the same process parameters. A significant increasein process reliability is thus also achieved in this manner.

The process according to the invention is carried out in detail asfollows: Small amounts of a precursor having an OH number of from 5 to500 mg KOH/g are initially introduced as the starting medium into thereactor under an inert gas atmosphere, for example nitrogen or noblegas. The amount of precursor which is advantageously employed as thestarting medium depends on the particular reactor and stirrer geometryand the design of the heating and cooling device. It is to be chosensuch that the reaction mixture can be readily stirred, and moreover theheat of reaction should be easy to remove or the contents of the reactorshould be easy to heat up. The most diverse compounds having OH numberof from 5 to 500 mg KOH/g can be employed as precursors. Preferredprecursors are e.g. addition products of low molecular weight startercompounds having Zerewitinoff-active hydrogen atoms and alkylene oxides,polyester polyols or polycarbonate polyols and hydroxylatedtriglycerides or hydroxylated fatty acid derivatives. If the process isto be carried out by the continuous starter compound metering process, asmall amount of a previously prepared batch of the product to beprepared itself is often used as the starting medium. Since the catalystconditioning process according to the invention is carried out in thetemperature range from 0 to 80° C., it may be appropriate to free thestarting medium from traces of water before the addition of thecatalyst, such as for example by stripping with nitrogen or inert gasesat temperatures of higher than 80° C. The upper temperature of thetemperature range suitable for this process is limited only by thethermal stability of the starting medium.

An inert organic solvent, such as toluene and/or THF, can moreover beadded, for example to lower the viscosity of the starting medium. Theamount of solvent in such cases is conventionally 10 wt. % to 30 wt. %,based on the total amount of the batch. The process is preferablycarried out without a solvent. The DMC catalyst is added to the startingmedium. Its concentration, calculated with respect to the amount of endproduct, is 10 to 1,000 ppm. A small amount of alkylene oxide, up to 20wt. %, based on the amount of starting medium employed, can now alsoalready be added to the catalyst-containing starting medium, which hasadvantageously been dried by stripping with inert gases at 0 to 80° C.

The conditioning of the catalyst is preferably carried out at atemperature of from 0° C. to 80° C., preferably from 20° C. to 60° C.,by dispersing the catalyst in the starting medium for 5 min to 4 hours,preferably 15 min to 2 hours. The dispersing is preferably carried outby stirring the catalyst-containing starting medium. The stirrer speedis preferably 40 to 800 rpm. Further possibilities are pumping of thecatalyst-containing starting mixture in circulation, the use of staticmixers or jet dispersing devices, or dispersion by means of ultrasound.If no readily volatile alkylene oxides have yet been metered in, thestarting medium can also be freed from low molecular weight impurities,such as e.g. water, by evacuation and/or stripping with inert gaseswithin the conditioning time. Stripping or evacuation is preferablycarried out for 15 to 60 min.

The catalyst is now activated by heating to temperatures of from 80 to160° C., preferably 100 to 140° C., very particularly preferably 120 to140° C. For this procedure, if this has not already happened in theconditioning phase, 5 to 20 wt. % of alkylene oxide, based on the amountof starting medium, is introduced into the reactor. The alkylene oxidecan be added before, during or after the heating up of the contents ofthe reactor to the activation temperature. The activation of thecatalyst manifests itself by an accelerated drop in the reactorpressure, by which the start of the alkylene oxide conversion isindicated. The desired amount of alkylene oxide or alkylene oxidemixtures can then be fed continuously to the reaction mixture, areaction temperature of from 20 to 200° C., but preferably from 50 to160° C. being chosen. The activation temperature is very particularlypreferably chosen as the reaction temperature. If a further startercompound or a further starter compound mixture is to be fed to thereactor by the continuous starter compound metering process, itsmetering can be started when 10 to 60 wt. % of alkylene oxide oralkylene oxide mixture, based on the amount of starting medium, hasalready been added to the starting medium. The metering rate for furtherstarter compounds or starter compound mixtures is preferably chosen suchthat after the end of the metering of the starter compound (mixture) asmall amount of further alkylene oxide (mixture) can still be metered into achieve the desired OH number. However, it is also possible to allowthe metering of the starter compound (mixture) and the metering of thealkylene oxide (mixture) to end simultaneously.

In one variant of the preparation of polyether polyols, the total amountof the starter compounds employed for the preparation of the polyetherpolyols is already present in the starting medium during theconditioning of the DMC catalysts. Only alkylene oxide (mixture) is thenstill metered in continuously after activation of the catalyst.

After the end of the metering of the alkylene oxide (mixture), anafter-reaction phase follows, in which the decrease in the concentrationof unreacted alkylene oxide is preferably quantified by monitoring thepressure. When a constant pressure is reached, the product can bedischarged from the reactor, optionally after a thorough heating phase.

A process for the fully continuous preparation of polyether polyols suchas is described in WO 98/03571 is also an important process alternative.In this process, catalyst must also be fed continuously to a reactor,alongside alkylene oxide and starter mixture. For this purpose, aconcentrated dispersion containing 0.1 to 10 wt. % of conditionedcatalyst is prepared by the catalyst conditioning process describedabove in the absence of alkylene oxides, and is then fed to the reactorin the fully continuous polyether polyol preparation process. DMCcatalysts which are suitable for the process according to the inventionare known in principle. As already mentioned, DMC catalysts are usedabove all for the preparation of polyether polyols by polyaddition ofalkylene oxide on to starter compounds having active hydrogen atoms (seee.g. U.S. Pat. No. 3,404,109, U.S. Pat. No. 3,829,505, U.S. Pat. No.3,941,849 and U.S. Pat. No. 5,158,922), since the use of DMC catalystshas the effect of a reduction in the content of monofunctionalpolyethers having terminal double bonds, so-called mono-ols, comparedwith the conventional preparation of polyether polyols by means ofalkali catalysts. Moreover, base-sensitive functional groups, such as,for example, carbonyl functions or ester groups, withstand DMC-catalyzedalkylene oxide addition reactions intact. Improved DMC catalysts, whichare described e.g. in U.S. Pat. No. 5,470,813, EP-A 700 949, EP-A 743093, EP-A 761 708, WO 97/40086, WO 98/16310 and WO 00/47649, furthermorehave, as already mentioned in the introductory sections, anexceptionally high activity and render possible preparation of polyetherpolyols at very low catalyst concentrations (25 ppm or less), so that itis no longer necessary to separate off the catalyst from the finishedproduct. Examples include the highly active DMC catalysts described inEP-A 700 949, which also contain a polyether having a number-averagemolecular weight of greater than 500 g/mol, alongside a double metalcyanide compound (e.g. zinc hexacyanocobaltate(III)) and an organiccomplexing ligand (e.g. tert-butanol).

Suitable alkylene oxides are, for example, ethylene oxide, propyleneoxide, 1,2- and 2,3-butylene oxide and styrene oxide. Propylene oxideand ethylene oxide are preferably used, individually or as mixtures. Ifvarious alkylene oxides are used, these can be metered in either as amixture or successively. In the case of the latter metering method, thepolyether chains have block structures. To obtain defined blockstructures in the process according to the invention, however, it isnecessary to end the continuous metering of starter compounds togetherwith or shortly before the end of the metering of the first alkyleneoxide block. Preferably, pure ethylene oxide or mixtures of propyleneoxide and ethylene oxide having a high ethylene oxide content aremetered in as the end block, so that the polyether polyols preparedcontain 40 to 100% of primary OH end group.

Further monomers which can be copolymerized with alkylene oxide by thisprocess are, for example, lactones, lactides, acid anhydrides, cycliccarbonates and carbon dioxide. Their use is described in U.S. Pat. No.3,538,043, U.S. Pat. No. 4,500,704, U.S. Pat. No. 5,032,671 and U.S.Pat. No. 6,646,100.

Suitable starter compounds for the continuous starter compound meteringprocess using DMC catalysts conditioned according to the inventionpreferably have functionalities of from 2 to 8. Examples are propyleneglycol, ethylene glycol, diethylene glycol, 1,2-butanediol,1,3-butanediol, 1,4-butanediol, hexanediol, pentanediol,3-methyl-1,5-pentanediol, 1,12-dodecanediol, glycerol,trimethylolpropane, triethanolamine, pentaerythritol, sorbitol, sucrose,hydroquinone, pyrocatechol, resorcinol, bisphenol F, bisphenol A,1,3,5-trihydroxybenzene, condensates of formaldehyde and phenol ormelamine or urea containing methylol groups, and Mannich bases. Mono- orpolyamines which can optionally be employed are ethylenediamine,1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine,ethanolamine, diethanolamine, diethylenetriamine, aniline, piperazine,the isomers of toluenediamine and the isomers of(diaminodiphenyl)methane. Starter compounds which are free from aminogroups are preferably used.

Polyester polyols are also suitable as starter compounds which are to bemetered in continuously or starting media which are to be initiallyintroduced into the reaction vessel. These can be prepared, for example,from organic dicarboxylic acids having 2 to 12 carbon atoms andpolyhydric alcohols, preferably diols, having 2 to 12 carbon atoms,preferably 2 to 6 carbon atoms. Possible dicarboxylic acids are, forexample: succinic acid, glutaric acid, adipic acid, suberic acid,azelaic acid, sebacic acid, decanedicarboxylic acid,dodecanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid,isophthalic acid and terephthalic acid. In this context, thedicarboxylic acids can be used either individually or in a mixture withone another. Instead of the free dicarboxylic acids, it is also possibleto employ the corresponding dicarboxylic acid derivatives, such as e.g.dicarboxylic acid mono- and/or diesters of alcohols having 1 to 4 carbonatoms or dicarboxylic acid anhydrides. Dicarboxylic acid mixtures ofsuccinic, glutaric and adipic acid in ratios of amounts of, for example,20-35/40-60/20-36 parts by wt., and in particular adipic acid arepreferably used. Examples of di- and polyhydric alcohols are ethanediol,diethylene glycol, 1,2- and 1,3-propanediol, dipropylene glycol,methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol,3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentylglycol,1,10-decanediol, 1,12-dodecanediol, glycerol, trimethylolpropane andpentaerythritol. 1,2-Ethanediol, diethylene glycol, 1,4-butanediol,1,6-hexanediol, glycerol, trimethylolpropane or mixtures of at least twoof the diols mentioned, in particular mixtures of ethanediol,1,4-butanediol and 1,6-hexanediol, glycerol and/or trimethylolpropane,are preferably used. Polyester polyols from lactones, e.g.ε-caprolactone, or hydroxycarboxylic acids, e.g. hydroxycaproic acid andhydroxyacetic acid, can furthermore be employed.

For preparation of such polyester polyols, the organic, aromatic oraliphatic polycarboxylic acids and/or polycarboxylic acid derivativesand polyhydric alcohols can be subjected to polycondensation without acatalyst or in the presence of esterification catalysts, expediently inan atmosphere of inert gases, such as e.g. nitrogen, helium or argon,and also in the melt at temperatures of from 150 to 300° C., preferably180 to 230° C., optionally under reduced pressure, until the desiredacid and OH numbers are reached. The acid number is preferably less than10 mg KOH/g, preferably less than 2.5 mg KOH/g.

In a preferred preparation process, the esterification mixture issubjected to polycondensation at the abovementioned temperatures undernormal pressure and then under a pressure of less than 500 mbar,preferably 1 to 150 mbar, to an acid number of from 80 to 30, preferably40 to 30. Possible esterification catalysts are, for example, iron,cadmium, cobalt, lead, zinc, antimony, magnesium, titanium and tincatalysts in the form of metals, metal oxides or metal salts. However,the polycondensation of aromatic or aliphatic carboxylic acids withpolyhydric alcohols can also be carried out in a liquid phase in thepresence of diluents and/or entraining agents, such as e.g. benzene,toluene, xylene or chlorobenzene, for removal of the water ofcondensation by azeotropic distillation.

The ratio of dicarboxylic acid (derivative) and polyhydric alcohol to bechosen to obtain a desired OH number, functionality and viscosity andthe alcohol functionality to be chosen can be determined in a simplemanner by the person skilled in the art.

Polycarbonates containing hydroxyl groups are furthermore suitable asstarter compounds which are to be metered in continuously or startingmedia which are to be initially introduced into the reaction vessel.Possible polycarbonates containing hydroxyl groups are those of the typeknown per se, which can be prepared e.g. by reaction of diols, such as1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol,triethylene glycol, tetraethylene glycol oligo-tetramethylene glycoland/or oligo-hexamethylene glycol, with diaryl carbonates and/or dialkylcarbonates, e.g. diphenyl carbonate, dimethyl carbonate andα-ω-bischloroformates or phosgene.

Against the background of the scarcity of petrochemical resources andthe adverse rating of fossil raw materials in ecobalances, the use ofraw materials from regenerable sources is also gaining increasingimportance in the preparation of polyols which are suitable for thepolyurethane industry. One possibility for the preparation of suchpolyols is the addition of alkylene oxides on to hydroxylatedtriglycerides, such as, for example, hydroxylated soya oil orhydroxylated rapeseed oil. Such starter compounds can be reacted withalkylene oxides particularly advantageously by the process according tothe invention. Other fatty acid derivatives, such as, for example, fattyacid monoalkyl esters, can of course also be hydroxylated and employedin the process according to the invention. The hydroxylatedtriglycerides and/or hydroxylated fatty acid derivatives can be eitherinitially introduced into the reaction vessel as the starting medium, orfed to the reactor continuously as starter compounds during the alkyleneoxide metering phase.

All the starter compounds or starting media can be employed individuallyor as mixtures. Small amounts (1 to 500 ppm) of organic or inorganicacids can moreover be added to the starter compounds and/or the startingmedium, as described in WO 99/14258.

An essential feature of the present invention is the reduced sensitivityof the DMC catalyst to many types of impurities in the starter compound(mixture) or in the starting medium which can be achieved by theconditioning. Involved purification operations on the starter compound(mixture) or the starting medium can thus be reduced to a minimum inmany cases, or avoided entirely. For example, the DMC catalyst does notreact particularly sensitively to water in the starter compound(mixture) even at high ratios of starter compound (mixture) to alkyleneoxide in the educt stream metered in; the consistently high catalystactivity even at relatively low amounts of catalyst manifests itself inlow alkylene oxide partial pressures during the reaction.

Anti-ageing agents, such as e.g. antioxidants, can optionally be addedto the polyols obtainable by the process according to the invention.

The polyols can be reacted, by themselves or optionally in a mixturewith further isocyanate-reactive components, with organicpolyisocyanates, optionally in the presence of blowing agents, in thepresence of catalysts and optionally with further additives, such ase.g. cell stabilizers, and in this way serve as components of solid orfoamed polyurethane materials.

EXAMPLES

Raw Materials Employed

Catalyst for the Alkylene Oxide Addition (DMC Catalyst):

Double metal cyanide catalyst made from zinc hexacyanocobaltate,tert-butanol and polypropylene glycol having a number-average molecularweight of 1,000 g/mol; as described in EP-A 700 949.

Polyol A

Trifunctional polyether of OH number 238, obtained by addition ofpropylene oxide on to glycerol.

Polyol B

Difunctional polyether of OH number 260, obtained by addition ofpropylene oxide on to propylene glycol.

Polyol C

Trifunctional polyether of OH number 56, obtained by addition ofpropylene oxide on to glycerol. Polyol C contained 200 ppm phosphoricacid.

Preparation of Hydroxylated Rapeseed Oil (Polyol D):

3,050 g rapeseed oil obtained from 00-rapeseed (erucic acid content: 0.3wt. %, content of free fatty acids: 0.6 wt. %, iodine number: 117 giodine/100 g, obtained from Campa Biodiesel, Ochsenfurt, Germany) wereinitially introduced into a glass flask under a nitrogen atmosphere andwere heated to 70° C. 370.4 g formic acid and 457.7 g hydrogen peroxide(as a 50% strength solution in water) in each case in 7 equal portionswere now added via two dropping funnels over a period of 7 hours. Theparticular hydrogen peroxide portion was metered directly after a formicacid portion. After addition of the last portion, the reaction mixturewas left to after-react for 1 hour at 70° C. and was then heated for 4hours at the reflux temperature (105° C.). The oxirane oxygen contentwas 0.051 wt. %. After the water and unreacted formic acid had beendistilled off, the product was heated thoroughly for 3 hours at 110° C.under a pressure of 1 mbar. The OH number of the hydroxylated rapeseedoil was 149.8 mg KOH/g, and its acid number was 5.63 mg KOH/g.

Example 1

0.39 g DMC catalyst was added to 750 g polyol A in a 10-liter autoclave.The contents of the reactor were then heated up to 60° C. and strippedfor 30 min, while stirring (450 rpm) and while passing through nitrogen(50 ml/min). The contents of the reactor were then stirred at 60° C.under 100 mbar for a further 60 min. Thereafter, the mixture was heatedto 130° C. and 80 g propylene oxide were added to the reactor with ametering rate of 200 g/hr, the pressure rising to 1.2 bar. Thesubsequent activation of the DMC catalyst manifested itself by anaccelerated drop in pressure. After activation of the catalyst had takenplace, a further 4,484.8 g propylene oxide were metered into theautoclave with a constant 1,087 g/hr. After a total of 100 g propyleneoxide (including the amount employed for activation of the catalyst) hadbeen metered, metering of 46 g propylene glycol (containing 750 ppmwater) was started with a constant metering rate of 22.75 g/hr. After atotal of 250 g propylene oxide (including the amount employed foractivation of the catalyst) had been metered, metering of 639.3 gglycerol (containing 2,000 ppm water and 75 ppm phosphoric acid) wasstarted with a constant metering rate of 177.5 g/hr. After the end ofthe metering in of propylene oxide, the mixture was left to after-reactfor a further 23 min at 130° C., and the product was heated thoroughlyat 130° C. in vacuo for 30 min. The maximum propylene oxide partialpressure, determined from the difference between the maximum reactorpressure and the pressure level reached at the end of the after-reactionphase, was 1.4 bar. The OH number of the product was 235.3 mg KOH/g.

Example 2

0.39 g DMC catalyst was added to 750.9 g polyol A in a 10-literautoclave. The contents of the reactor were then heated up to 60° C. andstripped for 30 min, while stirring (450 rpm) and while passing throughnitrogen (50 ml/min). The contents of the reactor were then stirred at60° C. under 100 mbar for a further 30 min. Thereafter, the mixture washeated to 130° C. and 80 g propylene oxide were added to the reactorwith a metering rate of 250 g/hr, the pressure rising to 1.2 bar. Thesubsequent activation of the DMC catalyst manifested itself by anaccelerated drop in pressure. After activation of the catalyst had takenplace, a further 4,484.9 g propylene oxide were metered into theautoclave with a constant 1,087 g/hr. After a total of 100 g propyleneoxide (including the amount employed for activation of the catalyst) hadbeen metered, metering of 46 g propylene glycol (containing 750 ppmwater) was started with a constant metering rate of 22.75 g/hr. After atotal of 250 g propylene oxide (including the amount employed foractivation of the catalyst) had been metered, metering of 639.6 gglycerol (containing 2,000 ppm water and 75 ppm phosphoric acid) wasstarted with a constant metering rate of 177.5 g/hr. After the end ofthe metering in of propylene oxide, the mixture was left to after-reactfor a further 1 hour at 130° C., and the product was heated thoroughlyat 130° C. in vacuo for 30 min. The maximum propylene oxide partialpressure, determined from the difference between the maximum reactorpressure and the pressure level reached at the end of the after-reactionphase, was 1.65 bar. The OH number of the product was 234.9 mg KOH/g.

Example 3

0.39 g DMC catalyst was added to 751 g polyol A in a 10-liter autoclave.The contents of the reactor were then heated up to 60° C. and strippedfor 30 min, while stirring (450 rpm) and while passing through nitrogen(50 ml/min). Thereafter, the mixture was heated to 130° C. and 80 gpropylene oxide were added to the reactor with a metering rate of 250g/hr, the pressure rising to 0.8 bar. The subsequent activation of theDMC catalyst manifested itself by an accelerated drop in pressure. Afteractivation of the catalyst had taken place, a further 4,484.9 gpropylene oxide were metered into the autoclave with a constant 1,087g/hr. After a total of 100 g propylene oxide (including the amountemployed for activation of the catalyst) had been metered, metering of46 g propylene glycol (containing 750 ppm water) was started with aconstant metering rate of 22.75 g/hr. After a total of 250 g propyleneoxide (including the amount employed for activation of the catalyst) hadbeen metered, metering of 640 g glycerol (containing 2,000 ppm water and75 ppm phosphoric acid) was started with a constant metering rate of177.5 g/hr. After the end of the metering in of propylene oxide, themixture was left to after-react for a further 30 min at 130° C., and theproduct was heated thoroughly at 130° C. in vacuo for 30 min. Themaximum propylene oxide partial pressure, determined from the differencebetween the maximum reactor pressure and the pressure level reached atthe end of the after-reaction phase, was 1.65 bar. The OH number of theproduct was 235.7 mg KOH/g.

Example 4

0.39 g DMC catalyst was added to 752.9 g polyol A in a 10-literautoclave. The contents of the reactor were then stripped at 20° C.,while stirring (450 rpm) and while passing through nitrogen (50 ml/min).The contents of the reactor were then stirred at 20° C. under 100 mbarfor a further 3 hours. Thereafter, the mixture was heated to 130° C. and80 g propylene oxide were added to the reactor with a metering rate of250 g/hr, the pressure rising to 1.4 bar. The subsequent activation ofthe DMC catalyst manifested itself by an accelerated drop in pressure.After activation of the catalyst had taken place, a further 4,484.9 gpropylene oxide were metered into the autoclave with a constant 1,087g/hr. After a total of 100 g propylene oxide (including the amountemployed for activation of the catalyst) had been metered, metering of46 g propylene glycol (containing 750 ppm water) was started with aconstant metering rate of 22.75 g/hr. After a total of 250 g propyleneoxide (including the amount employed for activation of the catalyst) hadbeen metered, metering of 640 g glycerol (containing 2,000 ppm water and75 ppm phosphoric acid) was started with a constant metering rate of177.5 g/h. After the end of the metering in of propylene oxide, themixture was left to after-react for a further 40 min at 130° C., and theproduct was heated thoroughly at 130° C. in vacuo for 30 min. Themaximum propylene oxide partial pressure, determined from the differencebetween the maximum reactor pressure and the pressure level reached atthe end of the after-reaction phase, was 0.95 bar. The OH number of theproduct was 236.0 mg KOH/g.

Example 5

0.39 g DMC catalyst was added to 754 g polyol A in a 10-liter autoclave.The contents of the reactor were then stripped at 20° C. for 30 min,while stirring (450 rpm) and while passing through nitrogen (50 ml/min).The contents of the reactor were then stirred at 20° C. under 100 mbarfor a further 114 min. Thereafter, the mixture was heated to 130° C. and80 g propylene oxide were added to the reactor with a metering rate of250 g/hr, the pressure rising to 1.7 bar. The subsequent activation ofthe DMC catalyst manifested itself by an accelerated drop in pressure.After activation of the catalyst had taken place, a further 4,484.9 gpropylene oxide were metered into the autoclave with a constant 1,087g/hr. After a total of 100 g propylene oxide (including the amountemployed for activation of the catalyst) had been metered, metering of46.2 g propylene glycol (containing 750 ppm water) was started with aconstant metering rate of 22.75 g/hr. After a total of 250 g propyleneoxide (including the amount employed for activation of the catalyst) hadbeen metered, metering of 639.9 g glycerol (containing 2,000 ppm waterand 75 ppm phosphoric acid) was started with a constant metering rate of177.5 g/hr. After the end of the metering in of propylene oxide, themixture was left to after-react for a further 33 min at 130° C., and theproduct was heated thoroughly at 130° C. in vacuo for 30 min. Themaximum propylene oxide partial pressure, determined from the differencebetween the maximum reactor pressure and the pressure level reached atthe end of the after-reaction phase, was 1.1 bar. The OH number of theproduct was 235.2 mg KOH/g.

Example 6 (Comparison)

0.39 g DMC catalyst was added to 750.3 g polyol A in a 10-literautoclave. The contents of the reactor were then stripped at 130° C. for30 min, while stirring (450 rpm) and while passing through nitrogen (50ml/min). 80 g propylene oxide were then added to the reactor at 130° C.with a metering rate of 250 g/hr. The catalyst already activated aftermetering of 30 g propylene oxide (maximum pressure reached: 0.5 bar),which manifested itself by an accelerated drop in pressure. Afteractivation of the catalyst had taken place, a further 4,484.5 gpropylene oxide were metered into the autoclave with a constant 1,087g/hr. After a total of 100 g propylene oxide (including the amountemployed for activation of the catalyst) had been metered, metering of46 g propylene glycol (containing 750 ppm water) was started with aconstant metering rate of 22.75 g/hr. After a total of 250 g propyleneoxide (including the amount employed for activation of the catalyst) hadbeen metered, metering of 639.4 g glycerol (containing 2,000 ppm waterand 75 ppm phosphoric acid) was started with a constant metering rate of177.5 g/hr. After the end of the metering in of propylene oxide, themixture was left to after-react for a further 30 min at 130° C., and theproduct was heated thoroughly at 130° C. in vacuo for 30 min. Themaximum propylene oxide partial pressure, determined from the differencebetween the maximum reactor pressure and the pressure level reached atthe end of the after-reaction phase, was 3.03 bar. The OH number of theproduct was 235.6 mg KOH/g.

Example 7

0.39 g DMC catalyst was added to 750.6 g polyol A in a 10-literautoclave. The contents of the reactor were then stripped at 60° C. for30 min, while stirring (450 rpm) and while passing through nitrogen (50ml/min). 80 g propylene oxide were then added to the reactor at 60° C.with a metering rate of 250 g/hr. The pressure rose to 0.7 bar duringthis operation. The contents of the reactor were than stirred under thispressure at 60° C. for a further 90 min. Thereafter, the mixture washeated to 130° C., the pressure rising to 2.15 bar. The subsequentactivation of the DMC catalyst manifested itself by an accelerated dropin pressure. After activation of the catalyst had taken place, a further4,484.9 g propylene oxide were metered into the autoclave at a constant1,087 g/hr. After a total of 100 g propylene oxide (including the amountemployed for activation of the catalyst) had been metered, metering of46 g propylene glycol (containing 750 ppm water) was started with aconstant metering rate of 22.75 g/hr. After a total of 250 g propyleneoxide (including the amount employed for activation of the catalyst) hadbeen metered, metering of 639.3 g glycerol (containing 2,000 ppm waterand 75 ppm phosphoric acid) was started with a constant metering rate of177.5 g/hr. After the end of the metering in of propylene oxide, themixture was left to after-react for a further 24 min at 130° C., and theproduct was heated thoroughly at 130° C. in vacuo for 30 min. Themaximum propylene oxide partial pressure, determined from the differencebetween the maximum reactor pressure and the pressure level reached atthe end of the after-reaction phase, was 1.15 bar. The OH number of theproduct was 236.2 mg KOH/g.

Example 8 (Comparison)

0.541 g DMC catalyst was added to 749.8 g polyol A in a 10-literautoclave. The contents of the reactor were then stripped at 130° C. for30 min, while stirring (450 rpm) and while passing through nitrogen (50ml/min). 80 g propylene oxide were then added to the reactor at 130° C.with a metering rate of 250 g/hr. The catalyst already activated aftermetering of 35 g propylene oxide (maximum pressure reached: 0.65 bar),which manifested itself by an accelerated drop in pressure. Afteractivation of the catalyst had taken place, a further 4,484.8 gpropylene oxide were metered into the autoclave with a constant 1,087g/hr. After a total of 100 g propylene oxide (including the amountemployed for activation of the catalyst) had been metered, metering of46.2 g propylene glycol (containing 750 ppm water) was started with aconstant metering rate of 22.75 g/hr. After a total of 250 g propyleneoxide (including the amount employed for activation of the catalyst) hadbeen metered, metering of 640.0 g glycerol (containing 1,000 ppm waterand 75 ppm phosphoric acid) was started with a constant metering rate of177.5 g/hr. After the end of the metering in of propylene oxide, themixture was left to after-react for a further 39 min at 130° C., and theproduct was heated thoroughly at 130° C. in vacuo for 30 min. Themaximum propylene oxide partial pressure, determined from the differencebetween the maximum reactor pressure and the pressure level reached atthe end of the after-reaction phase, was 0.7 bar. The OH number of theproduct was 235.5 mg KOH/g.

Example 9

0.37 g DMC catalyst was added to 749.9 g polyol A in a 10 l autoclave.The contents of the reactor were then stripped at 20° C. for 15 min,while stirring (450 rpm) and while passing through nitrogen (50 ml/min).Thereafter, the mixture was heated to 130° C. and 80 g propylene oxidewere added to the reactor at a metering rate of 250 g/h, the pressurerising to 2.2 bar. The subsequent activation of the DMC catalystmanifested itself by an accelerated drop in pressure. After activationof the catalyst had taken place, a further 4484.8 g propylene oxide weremetered into the autoclave at a constant metering rate of 1087 g/h.After a total of 100 g propylene oxide (including the amount employedfor activation of the catalyst) had been metered in, the metering in of46.0 g propylene glycol (containing 750 ppm water) was started at aconstant metering rate of 22.75 g/h. After a total of 250 g propyleneoxide (including the amount employed for activation of the catalyst) hadbeen metered in, the metering in of 639.3 g glycerol (containing 2,000ppm water and 75 ppm phosphoric acid) was started at a constant meteringrate of 177.5 g/h. After the end of the metering in of propylene oxide,the mixture was left to after-react for a further 30 min at 130° C., andthe product was finally heated thoroughly at 130° C. in vacuo for 30min. The maximum propylene oxide partial pressure, determined from thedifference between the maximum reactor pressure and the pressure levelreached at the end of the after-reaction phase, was 1.12 bar. The OHnumber of the product was 238.2 mg KOH/g.

Example 10

0.36 g DMC catalyst was added to 750.1 g of the product from Example 9in a 10 l autoclave. The contents of the reactor were then stripped at20° C. for 15 min, while stirring (450 rpm) and while passing throughnitrogen (50 ml/min). Thereafter, the mixture was heated to 130° C. and80 g propylene oxide were added to the reactor at a metering rate of 250g/h, the pressure rising to 2.0 bar. The subsequent activation of theDMC catalyst manifested itself by an accelerated drop in pressure. Afteractivation of the catalyst had taken place, a further 4484.9 g propyleneoxide were metered into the autoclave at a constant metering rate of1087 g/h. After a total of 100 g propylene oxide (including the amountemployed for activation of the catalyst) had been metered in, themetering in of 46.1 g propylene glycol (containing 750 ppm water) wasstarted at a constant metering rate of 22.75 g/h. After a total of 250 gpropylene oxide (including the amount employed for activation of thecatalyst) had been metered in, the metering in of 639.3 g glycerol(containing 2,000 ppm water and 75 ppm phosphoric acid) was started at aconstant metering rate of 177.5 g/h. After the end of the metering in ofpropylene oxide, the mixture was left to after-react for a further 40min at 130° C., and the product was finally heated thoroughly at 130° C.in vacuo for 30 min. The maximum propylene oxide partial pressure,determined from the difference between the maximum reactor pressure andthe pressure level reached at the end of the after-reaction phase, was1.12 bar. The OH number of the product was 235.1 mg KOH/g.

The test parameters and the test results of Examples 1 to 10 aresummarized below in Table I.

TABLE I Water Max. PO Conditioning Catalyst in OH # partial Temp. Timeconc. glycerol [mg press. Example [° C.] [min] [ppm] [ppm] KOH/g] [bar]1 yes 60 90 65 2,000 235.3 1.4 2 yes 60 60 65 2,000 234.9 1.65 3 yes 6030 65 2,000 235.7 1.65 4 yes 20 210  65 2,000 236.0 0.95 5 yes 20 144 65 2,000 235.2 1.10 C-6 no — — 65 2,000 235.6 3.03  7* yes 60 120  652,000 236.2 1.15 C-8 no — — 90 1,000 235.5 0.70 9 yes 20 15 62 2,000238.2 1.12 10  yes 20 15 68 2,000 235.1 1.12 *In this example, propyleneoxide was already added to the reactor during the conditioning phase.

Catalyst concentration in Table I above is given with respect to the endproduct.

Comparison Example 8 shows that by increasing the amount of catalyst anddrying the glycerol, a smooth course of reaction, detectable from therelatively low propylene oxide partial pressure, can also be achievedwithout using the conditioning process. Such a process is of course notdesirable because of the prior purification operation and the highamount of catalyst to be employed.

Example 11

0.24 g DMC catalyst was added to 300 g polyol C in a 10-liter autoclave.The contents of the reactor were then stripped at 60° C. for 30 min,while stirring (450 rpm) and while passing through nitrogen (50 ml/min).Thereafter, the contents of the reactor were stirred for a further 90min at 60° C. under 100 mbar. Thereafter, the mixture was heated to 130°C. and a mixture of 3.3 g ethylene oxide and 27.7 g propylene oxide wasmetered in. The pressure rose to 1.6 bar during this operation. Thesubsequent activation of the DMC catalyst manifested itself by anaccelerated drop in pressure. When the activation of the catalyst hadtaken place, a mixture of 127.4 g ethylene oxide and 1,042.4 g propyleneoxide was metered into the autoclave with a constant metering rate of601.1 g/hr. After a total of 100 g alkylene oxide mixture (including theamount employed for activation of the catalyst) had been metered,metering of 897.7 g polyol D was started with a constant metering rateof 600 g/hr. When the metering in of the alkylene oxide mixture hadended, the mixture was left to after-react for a further 45 min at 130°C., and the product was heated thoroughly at 130° C. in vacuo for 30min. The maximum alkylene oxide partial pressure, determined from thedifference between the maximum reactor pressure and the pressure levelreached at the end of the after-reaction phase, was 1.02 bar. The OHnumber of the product was 63.1 mg KOH/g.

Example 12 (Comparison)

0.25 g DMC catalyst was added to 300 g polyol C in a 10-liter autoclave.The contents of the reactor were then stripped at 130° C. for 30 min,while stirring (450 rpm) and while passing through nitrogen (50 ml/min).A mixture of 3.3 g ethylene oxide and 27.7 g propylene oxide was thenmetered in. The pressure rose to 1.5 bar during this operation. Thesubsequent activation of the DMC catalyst manifested itself by anaccelerated drop in pressure. When the activation of the catalyst hadtaken place, a mixture of 127.4 g ethylene oxide and 1,042.4 g propyleneoxide was metered into the autoclave with a constant metering rate of601.1 g/hr. After the metering of 897.7 g polyol D at a constantmetering rate of 600 g/hr had been started after a total of 100 galkylene oxide mixture (including the amount employed for activation ofthe catalyst) had been metered, the pressure in the reactor rose rapidlyto a value of 4.2 bar. At this pressure level, 40.6 g ethylene oxide and331.5 g propylene oxide had been metered in at this point in time, themetering of the alkylene oxide mixture was discontinued. During the3-hour after-reaction phase, the reactor pressure dropped only to 3.5bar, which indicated a complete deactivation of the catalyst. Theexperiment was therefore discontinued.

Example 13

0.24 g DMC catalyst was added to 300.6 g of the product from Example 9,containing 100 ppm DMC catalyst from its preparation, in a 10-literautoclave. The contents of the reactor were then stripped at 60° C. for30 min, while stirring (450 rpm) and while passing through nitrogen (50ml/min). Thereafter, the contents of the reactor were stirred for afurther 90 min at 60° C. under 100 mbar. Thereafter, the mixture washeated to 130° C. and a mixture of 3.3 g ethylene oxide and 27.7 gpropylene oxide was metered in. The pressure rose to 1.3 bar during thisoperation. The subsequent activation of the DMC catalyst manifesteditself by an accelerated drop in pressure. When the activation of thecatalyst had taken place, a mixture of 128.9 g ethylene oxide and1,042.3 g propylene oxide was metered into the autoclave with a constantmetering rate of 601.1 g/hr. After a total of 100 g alkylene oxidemixture (including the amount employed for activation of the catalyst)had been metered, metering of 905.8 g polyol D was started with aconstant metering rate of 600 g/hr. When the metering in of the alkyleneoxide mixture had ended, the mixture was left to after-react for afurther 105 min at 130° C., and the product was heated thoroughly at130° C. in vacuo for 30 min. The maximum alkylene oxide partialpressure, determined from the difference between the maximum reactorpressure and the pressure level reached at the end of the after-reactionphase, was 1.06 bar. The OH number of the product was 63.3 mg KOH/g.

Example 14

0.24 g DMC catalyst was added to 300.8 g polyol C and 898.7 g polyol Din a 10-liter autoclave. The contents of the reactor were then strippedat 60° C. for 30 min, while stirring (450 rpm) and while passing throughnitrogen (50 ml/min). Thereafter, the contents of the reactor werestirred for a further 90 min at 60° C. under 100 mbar. The mixture wasthen heated to 130° C. and a mixture of 20.0 g ethylene oxide and 100.0g propylene oxide was metered in. The pressure rose to 3 bar during thisoperation. The subsequent activation of the DMC catalyst manifesteditself by an accelerated drop in pressure. When the activation of thecatalyst had taken place, a mixture of 112.3 g ethylene oxide and 950.6g propylene oxide was metered into the autoclave with a constantmetering rate of 501 g/hr. When the metering in of the alkylene oxidemixture had ended, the mixture was left to after-react for a further 40min at 130° C., and the product was heated thoroughly at 130° C. invacuo for 30 min. The maximum alkylene oxide partial pressure,determined from the difference between the maximum reactor pressure,which in this case was reached shortly before activation of thecatalyst, and the pressure level reached at the end of theafter-reaction phase, was 2.4 bar. The OH number of the product was 63.2mg KOH/g.

The test parameters and the test results of Examples 11 to 14 aresummarized below in Table II.

TABLE II Conditioning Catalyst Max. PO Temp. Time conc. OH # partialpress. Example [° C.] [min] [ppm] [mg KOH/g] [bar] 11 yes 60 120 10063.1 1.02 C-12 no — — 100 reaction reaction discontinued discontinued 13yes 60 120 112 63.3 1.06  14* yes 60 120 100 63.2 2.4  *In this example,in contrast to Example 11, all the starter compounds were initiallyintroduced into the reactor before the start of metering of the epoxide.Catalyst concentration in Table II above is given with respect to theend product.

Example 15

0.41 g DMC catalyst was added to 666.6 g polyol B in a 10-literautoclave. The contents of the reactor were then heated up to 60° C. andstripped for 30 min, while stirring (450 rpm) and while passing throughnitrogen (50 ml/min). 66.6 g propylene oxide were then added to thereactor at 60° C. The pressure rose to 0.6 bar during this procedure.The contents of the reactor were then stirred under this pressure at 60°C. for a further 60 min. Thereafter, the mixture was heated to 130° C.,the pressure rising to 1.8 bar. The subsequent activation of the DMCcatalyst manifested itself by an accelerated drop in pressure. Afteractivation of the catalyst had taken place, a further 2,435.7 gpropylene oxide were metered into the autoclave with a constant 648.3g/hr. After a total of 150 g propylene oxide (including the amountemployed for activation of the catalyst) had been metered, metering of831.2 g propylene glycol (containing 250 ppm water and 106 ppmphosphoric acid) was started with a constant metering rate of 250 g/hr.After the end of the metering in of propylene oxide, the mixture wasleft to after-react for a further 40 min at 130° C., and the product washeated thoroughly at 130° C. in vacuo for 30 min. The maximum propyleneoxide partial pressure, determined from the difference between themaximum reactor pressure and the pressure level reached at the end ofthe after-reaction phase, was 1.26 bar. The OH number of the product was347.7 mg KOH/g.

Example 16 (Comparison)

0.41 g DMC catalyst was added to 666.6 g polyol B in a 10-literautoclave. The contents of the reactor were then stripped at 130° C. for30 min, while stirring (450 rpm) and while passing through nitrogen (50ml/min). 66.6 g propylene oxide were then added to the reactor with ametering rate of 250 g/hr at 60° C. During the metering of this amountof propylene oxide, the pressure rose intermediately to 1.5 bar, and theDMC catalyst already activated in this phase, which manifested itself byan accelerated drop in pressure. It was intended to meter a further2,436.3 g propylene oxide into the autoclave with a constant meteringrate of 648.3 g/hr. After a total of 150 g propylene oxide (includingthe amount employed for activation of the catalyst) had been metered in,metering of 831.07 g propylene glycol (containing 250 ppm water) wasstarted with a constant metering rate of 250 g/hr. The pressure in thereactor rose rapidly to a value of 1.62 bar. The metering of propyleneoxide and propylene glycol was therefore interrupted. After anafter-reaction phase of 50 min, the metering of propylene oxide andpropylene glycol was started again under a pressure of 0.48 bar with theabovementioned metering rates. The reactor pressure rose significantlymore steeply than before to 1.8 bar, after which both metering streamswere stopped again. In the subsequent after-reaction phase of 70 minduration, the pressure dropped slowly to 0.8 bar. At this point in time,a total of only 469 g propylene oxide had been metered in, theexperiment was discontinued.

Example 17

0.41 g DMC catalyst was added to 666.0 g of the product from Example 13,containing 103 ppm DMC catalyst from its preparation, in a 10-literautoclave. The contents of the reactor were then heated up to 60° C. andstripped for 30 min, while stirring (450 rpm) and while passing throughnitrogen (50 ml/min). 66.6 g propylene oxide were then added to thereactor at 60° C. The pressure rose to 0.6 bar during this operation.The contents of the reactor were then stirred under this pressure at 60°C. for a further 60 min. Thereafter, the mixture was heated to 130° C.,the pressure rising to 2.0 bar. The subsequent activation of the DMCcatalyst manifested itself by an accelerated drop in pressure. When theactivation of the catalyst had taken place, a further 2,474.8 gpropylene oxide were metered into the autoclave with a constant 675.5g/hr. After a total of 150 g propylene oxide (including the amountemployed for activation of the catalyst) had been metered, metering of792.0 g propylene glycol (containing 280 ppm water and 106 ppmphosphoric acid) was started with a constant metering rate of 250 g/hr.When the metering in of the propylene oxide had ended, the mixture wasleft to after-react for a further 28 min at 130° C., and the product wasfinally heated thoroughly at 130° C. in vacuo for 30 min. The maximumpropylene oxide partial pressure, determined from the difference betweenthe maximum reactor pressure and the pressure level reached at the endof the after-reaction phase, was 1.5 bar. The OH number of the productwas 347.6 mg KOH/g.

Example 18

0.40 g DMC catalyst was added to 334.9 g of the product from Example 15,containing 120 ppm DMC catalyst from its preparation, in a 10-literautoclave. The contents of the reactor were then heated up to 60° C. andstripped for 30 min, while stirring (450 rpm) and while passing throughnitrogen (50 ml/min). 33.3 g propylene oxide were then added to thereactor at 60° C. The pressure rose to 0.48 bar during this operation.The contents of the reactor were then stirred under this pressure at 60°C. for a further 60 min. Thereafter, the mixture was heated to 130° C.,the pressure rising to 1.2 bar. The subsequent activation of the DMCcatalyst manifested itself by an accelerated drop in pressure. When theactivation of the catalyst had taken place, a further 2,763.1 gpropylene oxide were metered into the autoclave with a constant 703g/hr. After a total of 75 g propylene oxide (including the amountemployed for activation of the catalyst) had been metered, metering of869.9 g propylene glycol (containing 280 ppm water and 106 ppmphosphoric acid) was started with a constant metering rate of 250 g/hr.When the metering in of the propylene oxide had ended, the mixture wasleft to after-react for a further 20 min at 130° C., and the product wasfinally heated thoroughly at 130° C. in vacuo for 30 min. The maximumpropylene oxide partial pressure, determined from the difference betweenthe maximum reactor pressure and the pressure level reached at the endof the after-reaction phase, was 0.85 bar. The OH number of the productwas 348.5 mg KOH/g.

The test parameters and the test results of Examples 15 to 18 aresummarized below in Table III.

TABLE III Conditioning Catalyst Max. PO Temp. Time conc. OH # partialpress. Example [° C.] [min] [ppm] [mg KOH/g] [bar] 15 yes 60 90 103347.7 1.26 C-16 no — — 103 reaction reaction discontinued discontinued17 yes 60 90 120 347.6 1.50 18 yes 60 90 110 348.5 0.85 Catalystconcentration in Table III above is given with respect to the endproduct.

Although the invention has been described in detail in the foregoing forthe purpose of illustration, it is to be understood that such detail issolely for that purpose and that variations can be made therein by thoseskilled in the art without departing from the spirit and scope of theinvention except as it may be limited by the claims.

1. A process for conditioning double metal cyanide catalysts, in whichthe double metal cyanide (DMC) catalysts are dispersed in starting mediahaving an OH number of from about 5 to about 500 mg KOH/g, said startingmedia being selected from the group consisting of addition products ofstarter compounds having Zerewitinoff-active hydrogen atoms and alkyleneoxides, poly(ester) polyols, polycarbonate polyols, hydroxylatedtriglycerides, hydroxylated fatty acid derivatives and mixtures thereof,at a temperature of from about 0° C. to about 80° C. over a period offrom about 5 minutes to about 4 hours under pressures of from about 1mbar to about 10 bar.
 2. The process according to claim 1, wherein theconditioning is carried out under an inert gas atmosphere.
 3. Theprocess according to claim 1, wherein the conditioning is carried outunder an atmosphere containing inert gas and alkylene oxide.